Surface Modification of Li-rich Layered Li1.2Mn0.54Ni0.13Co0.13O2 Oxide with Fe2O3 As Cathode Material for Li-ion Batteries

Li-rich layered cathode is successfully prepared by the co-precipitation method, and subsequent surface modification of amorphous Fe2O3 coating is conducted to promote the cycling durability. The results reveal that amorphous Fe2O3 is well distributed on the secondary particles and does not change the intrinsic layered structure of the cathode material accordingly. Surface modification of Fe2O3 improves the initial coulomb efficiency, cycle stability, and rate capacity of the layered cathode. Especially, the 2 wt% Fe2O3 coated cathode material exhibits the highest initial discharge capacity of 267.5 mAh g(-1) at 0.1C and still remains 139.3 mAh g(-1) at 5C. Moreover, a capacity retention of 87.7% could be delivered even after 300 cycles at 1C on the 2 wt% Fe2O3 coated cathode, displaying distinctly high structural integrity and cycling stability, while the value of the pristine sample reaches only 70.8%. Meanwhile, the Fe2O3 coating stabilizes the electrode/electrolyte interface and lowers the charge transfer resistance. The above features after the introduction of the Fe2O3 protective layer could be ascribed to the suppression of the direct contract and corrosion of the cathode with the electrolyte, which effectively accelerates the Li+ diffusion and inhibits the transition from layered to spinel structure.